This invention relates generally to power operated doors for mass transit vehicles and more particularly concerns door operators of the type wherein big-parting door panels are moved into and out of a pocket opening in the side wall of a transit vehicle and over and away from said opening to permit passenger travel into and out of said vehicle. Generally speaking, plug doors are used on vehicles where, in a closed and plugged position, the door panels are positioned in a pocket opening in the vehicle side wall, thereby becoming in a closed and plugged position, essentially part of the side wall. This type of construction minimizes interference with the car structure and presents an uninterrupted car body surface.
Plug doors have been in use for a substantial period of time. Operators of this kind are disclosed in U.S. Pat. Nos. 5,142,823 and 5,483,769. In addition, a certain plug door operator bearing the trade name ESCO-DOOR and marketed by Transferia Tebel also provides plug door operation.
Although the above mentioned operators are reasonably effective, certain shortcomings have been encountered in use, particularly in respect to complicated linkages between the electric prime mover and operator carriage, resulting in reduced reliability. Other shortcomings of these earlier designs include spring actuated over center locking of the plug and plug carriage, use of telescoping hangers incorporating poorly controlled door motion for individual door panels, and lever actuated plugging/unplugging links operated by extended motor shafts.
The invention disclosed herein overcomes the above-mentioned difficulties through the use of an integral carriage containing all operator elements. The plugging and unplugging movement is obtained through the use of a single shaft drive motor mounted on the carriage providing both panel door motion and plug/unplug motion through the use of planetary gearing.
Also, guidance for the door panel lower edges is provided by a lever operated vertical shaft actuated by the carriage during plugging and unplugging movements into and out of the car door pocket.
Therefore, an object of this invention is to provide a powered door operator for bi-parting door panels including plugging and unplugging operations wherein the entire drive system is mounted on a carriage movable into and out of the car door pocket.
It is a further object of this invention to provide a powered plug door operator for bi-parting doors wherein a combination of planetary and straight gearing provides door panel movement over and away from an opening in the car side wall and door panel plugging into a car side wall door pocket.
It is a further object of the invention to provide a plug door operator wherein in the door closed and plugged position doors are held in the door pocket through over-center linkage geometry.
It is yet an additional object of the invention to provide a plug door operator wherein individual bi-parting door panel hangers are of a simple non-telescoping design.